Mary Morstan has received a pearl in the post every year since her father's disappearance. This leads Holmes and Watson to the truth about a secret pact between four convicts during the Indian Rebellion of 1857.
2021
2005
1993
1960
1992
1987
2025
2019
1930
1979
1963
1991
2007
1933
1990
2018
1938
